Population receptive field analysis of the primary visual cortex complements perimetry in patients with homonymous visual field defects.

Injury to the primary visual cortex (V1) typically leads to loss of conscious vision in the corresponding, homonymous region of the contralateral visual hemifield (scotoma). Several studies suggest that V1 is highly plastic after injury to the visual pathways, whereas others have called this conclusion into question. We used functional magnetic resonance imaging (fMRI) to measure area V1 population receptive field (pRF) properties in five patients with partial or complete quadrantic visual field loss as a result of partial V1+ or optic radiation lesions. Comparisons were made with healthy controls deprived of visual stimulation in one quadrant ["artificial scotoma" (AS)]. We observed no large-scale changes in spared-V1 topography as the V1/V2 border remained stable, and pRF eccentricity versus cortical-distance plots were similar to those of controls. Interestingly, three observations suggest limited reorganization: (i) the distribution of pRF centers in spared-V1 was shifted slightly toward the scotoma border in 2 of 5 patients compared with AS controls; (ii) pRF size in spared-V1 was slightly increased in patients near the scotoma border; and (iii) pRF size in the contralesional hemisphere was slightly increased compared with AS controls. Importantly, pRF measurements yield information about the functional properties of spared-V1 cortex not provided by standard perimetry mapping. In three patients, spared-V1 pRF maps overlapped significantly with dense regions of the perimetric scotoma, suggesting that pRF analysis may help identify visual field locations amenable to rehabilitation. Conversely, in the remaining two patients, spared-V1 pRF maps failed to cover sighted locations in the perimetric map, indicating the existence of V1-bypassing pathways able to mediate useful vision.

Assessment of functional and morphometric endpoints in patients with non-arteritic anterior ischemic optic neuropathy (NAION).

BACKGROUND: The primary objective of this bi-center explorative pilot study was the quantitative assessment of visual field defects and retinal nerve fiber layer thickness (RNFT) over 6 months in patients with acute non-arteritic anterior ischemic optic neuropathy (NAION), in order to elucidate the natural course of NAION and provide a reference dataset for future treatment studies. METHODS: 16 patients (age 41-80 years, nine males, seven females) suffering from acute NAION and presenting within 7 days after onset of symptoms were included in this study. The following examinations were carried out at the initial visit (month 0) and at months 2, 4 and 6: entire (90°) visual field examination with automated static white-on-white perimetry, quantified by mean defect (MD); peripapillary retinal nerve fiber layer thickness (RNFT) measurement with spectral domain optical coherence tomography (SD-OCT); assessment of distant best correct visual acuity (D-BCVA) and a quantification of the relative afferent pupillary defect (RAPD) using the swinging flashlight test with neutral density filters. Perimetric Mean Defect (MD) and RNFT values were each compared between the consecutive visits using the non-parametric Friedman test. RESULTS: The initial MD was 6.2 dB (IQR 5.0-7.4) without significant changes further on. RNFT was 183 µm (IQR 148-252) initially, decreased significantly at month 2 (78 µm (IQR 71-93) and further at month 4 (64 µm (IQR 58-74) and 6 (61 µm (IQR 52-81), Friedman test, p < 0.001). Initially, RNFT was above normal limits (due to swelling) in 15/16 patients; at month 2 it was below normal limits in 13/16 patients, at month 4 in 12/13 patients and at month 6 in 9/10 patients. 7/16 patients exhibited segmental swelling of the optic disc, whereas the entire circumference of the optic disc showed RNFL thickening in 9/16 patients. CONCLUSION: Functional deficits were present directly after onset of NAION and did not change relevantly further on. Morphological changes comprise severe swelling after onset of NAION, which rapidly turns into atrophy. Already after 2 months more than 80 % of the patients showed a RNFT below normal limits. Progressive RNFL thinning between month 2 and month 4 suggests ongoing atrophy, whereas a stable morphologic end point is reached after month 4.

Specification of progression in glaucomatous visual field loss, applying locally condensed stimulus arrangements.

PURPOSE: The goal of this work was to (i) determine patterns of progression in glaucomatous visual field loss, (ii) compare the detection rate of progression between locally condensed stimulus arrangements and conventional 6 degrees x 6 degrees grid, and (iii) assess the individual frequency distribution of test locations exhibiting a local event (i.e., an abrupt local deterioration of differential luminance sensitivity (DLS) by more than -10 dB between any two examinations). METHODS: The visual function of 41 glaucomatous eyes of 41 patients (16 females, 25 males, 37 to 75 years old) was examined with automated static perimetry (Tuebingen Computer Campimeter or Octopus 101-Perimeter). Stimuli were added to locally enhance the spatial resolution in suspicious regions of the visual field. The minimum follow-up was four subsequent sessions with a minimum of 2-month (median 6-month) intervals between each session. Progression was identified using a modified pointwise linear regression (PLR) method and a modified Katz criterion. The presence of events was assessed in all progressive visual fields. RESULTS: Eleven eyes (27%) showed progression over the study period (median 2.5 years, range 1.3-8.6 years). Six (55%) of these had combined progression in depth and size and five eyes (45%) progressed in depth only. Progression in size conformed always to the nerve fiber course. Seven out of 11 (64%) of the progressive scotomata detected by spatially condensed grids would have been missed by the conventional 6 degrees x 6 degrees grid. At least one event occurred in 64% of all progressive eyes. Five of 11 (46%) progressive eyes showed a cluster of events. CONCLUSIONS: The most common pattern of progression in glaucomatous visual fields is combined progression in depth and size of an existing scotoma. Applying individually condensed test grids remarkably enhances the detection rate of glaucomatous visual field deterioration (at the expense of an increased examination time) compared to conventional stimulus arrangements.

The normal age-corrected and reaction time-corrected isopter derived by semi-automated kinetic perimetry.

PURPOSE: To determine the increase in isopter extent, resulting from the measurement of, and correction for, individual reaction time (RT; the latency between stimulus presentation and individual patient response), derived under the standardized conditions of semi-automated kinetic perimetry (SKP), and to model the age- and RT-corrected normative isopter values for SKP applicable to any Goldmann stimulus combination. DESIGN: Cross-sectional observational study. PARTICIPANTS: Eighty-three healthy participants aged 10 to 80 years (11-12 participants per decade of age). METHODS: One eye of each participant underwent SKP using the Octopus 101 perimeter (Haag-Streit, Koeniz, Switzerland). Four Goldmann stimulus combinations, III4e at 25 degrees/second, III4e at 5 degrees/second, I3e at 5 degrees/second, and I2e at 2 degrees/second, were presented centripetally (i.e., in a direction toward the center of the bowl) along the 8 cardinal meridia in random order. The local kinetic threshold (LKT) for each stimulus combination along each meridian was corrected for the angular distance traveled during the individual geometric mean RT and was modeled in terms of the covariables stimulus size, stimulus luminance, meridian, and age, and then presented in terms of a graphical reference plot. MAIN OUTCOME MEASURES: The variation of the LKT with RT, stimulus combination, meridian, and age. RESULTS: The median of the individual geometric mean RTs initially decreased and then increased with increase in age and was greater for stimulus combinations producing small isopters compared with those generating large isopters. Reaction time-corrected LKTs were fitted optimally by a multiple regression model (R2 = 0.86). For large (> or =size III) and intense (4e) stimuli, RT-corrected LKTs were independent of age and mainly were influenced by instrument- and facial anatomy-related characteristics. Reaction time-corrected LKTs, particularly for small (< or = size II) stimuli, exhibited a clear age dependence above the age of 40 years particularly for reduced luminance stimuli (< or = 2e), with an approximate reduction in angular extent of 2 degrees per decade for the I1e stimulus. CONCLUSIONS: The development of a graphical reference plot with mean isopters and accompanying reference intervals for age- and RT-corrected SKP, applicable to any individual patient, should facilitate the evaluation of clinical data and the implementation of a computerized alternative to manual Goldmann kinetic perimetry.

Validation of a new static perimetric thresholding strategy (GATE).

AIMS: To validate the EyeSuite version of German Adaptive Threshold Estimation (GATE), a new thresholding algorithm for automated static perimetry. METHODS: Specification of agreement and its clinical evaluation as validation criteria. Comparison of local differential luminance sensitivity (DLS) and test time values between the prototype version of GATE (GATEp) and a clinical trial version, implemented in EyeSuite (GATEe), by means of modified Bland-Altman plots. All examinations were performed on the Octopus 900 perimeter (Haag-Streit Inc., Köniz, Switzerland). Visually impaired patients (anterior ischaemic optic neuropathy [n=3], glaucomatous optic neuropathy [n=15], (post-)chiasmal visual pathway lesion [n=6], retinitis pigmentosa [n=6]) were either tested with grid 30A (30° excentricity, 83 test locations) or grid 84NO (90° excentricity, 109 test locations, patients with RP only). RESULTS: The comparison of local DLS values showed good-to-acceptable agreement between GATEp and GATEe (bias <2 dB, limits of agreement [LOA] <5 dB) and very good repeatability for GATEp (bias <0.5 dB, LOA<3 dB). Median test times for GATEp and GATEe were 7.8  and 8.8 min for the 30° grid and 6.7  and 7.8 min for the 90° grid. CONCLUSIONS: GATEp and GATE, implemented in the commercially available EyeSuite software package (GATEe), show good agreement regarding local differential luminance sensitivity. GATEe can thus be also recommended for clinical practice. CLINICAL TRIAL NUMBER: NCT01265628.

[Quantification of isopters using semiautomated kinetic perimetry (SKP) in glaucoma patients with advanced retinal nerve fiber layer (RNFL) loss]. / Pomiar powierzchni izopter z uzyciem pólautomatycznej perymetrii kinetycznej (PPK) u pacjentów z zaawansowana jaskra.

PURPOSE: To quantify the area of isopters obtained using a new technique of kinetic visual field examination--semi-automated kinetic perimetry (SKP)--in case of advanced retinal nerve fiber layer (RNFL) loss, caused by glaucoma. MATERIAL AND METHODS: Forty-one subjects (19 men, 22 women; mean age 66.5 +/- 12.5 years) suffering from open-angle glaucoma (30 patients), normal tension glaucoma (5 patients), juvenile glaucoma (2 patients) and PEX glaucoma (4 patients) were examined, using SKP program implemented in Octopus 101 instrument (Haag-Streit, Koeniz, Switzerland). One eye of each patient was tested using three stimuli according to the Goldmann classification. The stimuli III4e and I4e were obligatory. Additionally one stimulus (I3e or I2e) was used depending on the character of the defect. The stimulus angular velocity was kept constant at the level of 3 degrees/s. Obtained visual field (VF) results were classified according to the Aulhorn classification into stage III (26 VF) and IV (15 VF). The areas of isopters were measured in deg2. RESULTS: The mean area of isopter III4e was 9860 deg2, I4e--5171 deg2, I3e--1093 deg2, I2e--1093 deg2 in the group of Aulhorn stage III. In the group of Aulhorn stage IV the mean area of isopter III4e was 7488 deg2, I4e--3736 deg2, I3e--1109 deg2 and I2e--818 deg2. The mean test time was 16 min. (range 9-25 min.), 15.7 min. in the group of Aulhorn stage III and 16.5 min. in the group of Aulhorn stage IV, respectively. CONCLUSION: SKP seems to be an effective method for quantitative assessment and evaluation of isopter and scotoma areas (in deg2). In this study it was demonstrated that in case of more advanced stages of glaucomatous visual field loss (Aulhorn stage IV), the areas of isopters appeared to be smaller.

[Comparison of SKP (semi-automated kinetic perimetry) and SASP (suprathreshold automated static perimetry) techniques in patients with advanced glaucoma]. / Porównanie zastosowania pólautomatycznej perymetrii kinetycznej (PPK) oraz nadprogowej perymetrii statycznej (SASP) u chorych z zaawansowana jaskra.

PURPOSE: To compare the results of conventional suprathresold automated static perimetry (SASP) and a new method of kinetic visual field examination (semi-automated kinetic perimetry--SKP) in patients with advanced retinal nerve fibre layer (RNFL) defects, caused by glaucoma. MATERIAL AND METHODS: Nineteen patients (10 women and 9 men) suffering from advanced open-angle glaucoma (17 patients) and low tension glaucoma (2 patients) were enrolled in this study. The mean age was 65.3 years (range 49.0-82.9 years). One eye of each subject was examined with SKP and SASP, both implemented in Octopus 101 perimeter (Haag-Streit, Koeniz, Switzerland) on the same day. The examiner using SKP did not know the SASP results. The static visual field examination was performed first. In order to compare visual fields results obtained with both methods, only central 30 degree area of the visual fields was taken into consideration. The area obtained by creating a virtual isopter (option of SKP software) located between the position of defective and intact visual field regions of SASP and the area of I4e isopter obtained with SKP (stimulus angular velocity 3 degrees/s) were measured in deg2 and compared. RESULTS: The mean area (+/-SD) of I4e isopter obtained with SKP was 1882 deg2 (+/- 510 deg2) and the mean area of SASP 30 degree visual field was 1737 deg2 (+/- 546 deg2). This difference was not statistically significant. CONCLUSION: Quantitative comparison of static and kinetic perimetry is a difficult task to perform. The SKP software offers a possibility of direct quantitative assessment of the area of each isopters in deg2. This study shows that the results of visual field examinations obtained with both methods in this group do not differ significantly between SASP and SKP.

[Applicability of semi-automated kinetic perimetry (SKP) in the assessment of the visual field loss due to retinitis pigmentosa]. / Zastosowanie pólautomatycznej perymetrii kinetycznej (PPK) do oceny ubytków w polu widzenia spowodowanych przez zwyrodnienie barwnikowe siatkówki.

PURPOSE: To assess the applicability of a new technique of kinetic visual field examination--semi-automated kinetic perimetry (SKP)--in patients suffering from the visual field defects due to retinitis pigmentosa. METHODS: Thirty-five patients (19 women, 16 men: mean age 38.4 years) suffering from retinitis pigmentosa (10 with with Usher syndrome, one with Bardet-Biedl syndrome and one with Refsum syndrome) were examined using SKP software, implemented in Octopus 101 instrument (Haag-Streit, Koeniz, Switzerland). Three stimuli (1114e and 14e obligatory) were used to assess the hill of vision of each patient. The area of each isopter was measured in deg2. The test time was measured automatically in minutes. RESULTS: The visual field results were classified as complete or incomplete midperipheral "ring scotoma" (group I--13 patients) and concentric loss of the visual field (group II--22 patients). The area of 1114e isopter was 6147.5 deg2 in the group I and 1961.7 deg2 in the group II. The area of 14e isopter was 1468.4 deg2 and 781.7 deg2, respectively. The mean test time was 10 min. (range 4-20 min.): 8 min. in the group I and 13 min. in the group II. CONCLUSIONS: There is a large diversity of patterns of the visual field loss in retinitis pigmentosa. SKP, in contrary to widely used manual perimeter, gives a possibility of quantification of the visual field area. Future studies may be able to monitor the progression of the visual field loss caused by retinitis pigmentosa.

Spatial pattern of glaucomatous visual field loss obtained with regionally condensed stimulus arrangements.

PURPOSE: To assess the spatial distribution of glaucomatous visual field defects (VFDs) obtained with regionally condensed stimulus arrangements. METHODS: Sixty-three eyes of 63 glaucoma subjects were examined with threshold-estimating automated static perimetry (full threshold 4-2-1 dB strategy with at least three reversals) on an automatic campimeter or a full-field perimeter. Stimuli were added by the examiner to regionally enhance spatial resolution in regions that were suspicious for a glaucomatous VFD. These regions were characterized by contiguous local VFDs, attributable to the retinal nerve fiber bundle course according to the impression of the examiner. The added stimulus locations were subsets of a predefined, dense perimetric grid. All VFD locations with P < 0.05 (total deviation plots) were assessed by superimposing the visual field records of all participants. RESULTS: Glaucomatous VFD loss occurred more frequently in the upper than in the lower hemifield, with a typical retinal nerve fiber-related pattern and a preference of the nasal step region. More than 50% of the eyes with predominantly mild to moderate glaucomatous field loss showed defective locations in the immediate superior paracentral region within an eccentricity of 3°. CONCLUSIONS: Conventional thresholding white-on-white perimetry with regionally enhanced spatial resolution reveals that glaucomatous visual field loss affects the immediate paracentral area, especially the upper hemifield, in many eyes with only mild to moderate glaucomatous visual field loss. Detailed knowledge about the spatial pattern and the local frequency distribution of glaucomatous VFDs is an essential prerequisite for creating regionally condensed stimulus arrangements for adequate detection and follow-up of functional glaucomatous damage.

Comparison of the new perimetric GATE strategy with conventional full-threshold and SITA standard strategies.

PURPOSE: A new, fast-threshold strategy, German Adaptive Thresholding Estimation (GATE/GATE-i), is compared to the full-threshold (FT) staircase and the Swedish Interactive Thresholding Algorithm (SITA) Standard strategies. GATE-i is performed in the initial examination and GATE refers to the results in subsequent examinations. METHODS: Sixty subjects were recruited for participation in the study: 40 with manifest glaucoma, 10 with suspected glaucoma, and 10 with ocular hypertension. The subjects were evaluated by each threshold strategy on two separate sessions within 14 days in a randomized block design. RESULTS: SITA standard, GATE-i, and GATE thresholds were 1.2, 0.6, and 0.0 dB higher than FT. The SITA standard tended to have lower thresholds than those of FT, GATE-i, and GATE for the more positive thresholds, and also in the five seed locations. For FT, GATE-i, GATE, and SITA Standard, the standard deviations of thresholds between sessions were, respectively, 3.9, 4.5, 4.2, and 3.1 dB, test-retest reliabilities (Spearman's rank correlations) were 0.84, 0.76, 0.79, and 0.71, test-retest agreements as measured by the 95% reference interval of differences were -7.69 to 7.69, -8.76 to 9.00, -8.40 to 8.56, and -7.01 to 7.44 dB, and examination durations were 9.0, 5.7, 4.7, and 5.6 minutes. The test duration for SITA Standard increased with increasing glaucomatous loss. CONCLUSIONS: The GATE algorithm achieves thresholds that are similar to those of FT and SITA Standard, with comparable accuracy, test-retest reliability, but with a shorter test duration than FT.

Age-dependent normative values for differential luminance sensitivity in automated static perimetry using the Octopus 101.

PURPOSE: To determine age-dependent normative differential threshold values for the Octopus 101 instrument and to create a smooth mathematical model characterizing the age-dependency and asymmetry of the hill of vision. METHODS: Static automated perimetry within the central 30 degrees visual field (VF) was conducted with the Octopus 101 (background luminance 10 cd/m(2)) in 81 eyes of 81 ophthalmologically healthy subjects (11-12 per decade of age) aged 10-79 years. A 4-2-2 staircase strategy with three reversals was run. The test point grid consisted of 68 concentrically arranged points with test point condensation towards the VF centre, representing the approximately rotation-symmetrical 30 degrees hill of vision. Thresholds of differential luminance sensitivity (DLS) were estimated by the maximum likelihood method. A smooth mathematical model was fitted to the normative data. RESULTS: The model fit was satisfactory (r(2) = 0.74). Covariables were: age, eccentricity, angle and subject. Total random standard deviation (SD) was 1.75 dB. The residual SD exceeded 1.75 dB in the border region, was 1.5 dB within the centre and fell below 1.25 dB in a ring around the centre. Average thresholds of DLS varied with age quadratically. It is close to constant for the 10-40-year-old age group and declines ever more steeply thereafter. The effect of age on DLS in the VF increased with eccentricity. The greatest drop was located in the peripheral superior hemifield: at 25 degrees eccentricity the superior DLS was estimated to be 5.5 dB higher in 10-year-olds than in 75-year-olds. CONCLUSIONS: This new smooth model allows for the prediction of age-related normal threshold values for any stimulus location within the 30 degrees VF and thus for the calculation of global and local measures of defect such as mean defects or p-values for any type of stimulus.

Distribution of scotoma pattern related to chiasmal lesions with special reference to anterior junction syndrome.

PURPOSE: To evaluate pathogenetic mechanisms and frequency distribution of visual field defects (VFDs) in patients with chiasmal lesions. Secondly, to reconsider the existence of "Wilbrand's knee" as far as referable to the anterior junction syndrome. METHODS: Consecutive visual field records related to chiasmal lesions were retrieved from the Tuebingen Perimetric Database. In all cases, at least one eye was examined with the Tuebingen Automated Perimeter using a standardized grid of 191 static targets within the central 30 degrees visual field, and a threshold-related, slightly supraliminal strategy. VFDs were classified according to standard neuro-ophthalmological categories. RESULTS: Results from 153 consecutive patients (65 male, 88 female) were evaluable. The majority (65%) of chiasmal lesions was due to pituitary adenoma, followed by craniopharyngioma (12%), astrocytoma (9%), and meningioma (8%). Vascular lesions in this region occurred rarely (2%). Three per cent of all patients had no final diagnosis. The majority (22%) of scotomas was attributable to involvement of the temporal hemifield in both eyes, with true bitemporal hemianopia being a very rare event (1%). Anterior junction syndrome, characterized by advanced visual field loss affecting the visual field centre in one eye and (possibly subtle) defects respecting the vertical midline in the fellow eye, was the second most frequent classifiable VFD (13%). Homonymous hemianopic VFDs occurred in 11% of all cases. Nine per cent of all patients exhibited monocular VFDs which did not respect the vertical midline, whereas in 3% of the subjects the monocular VFDs did not cross the vertical meridian. Binasal defects and posterior junction syndrome also occurred seldom (< 1%). Nineteen per cent of all visual field records of patients with chiasmal lesions had results, which could not be classified unequivocally, and an identical portion was rated normal. CONCLUSION: In patients with chiasmal lesions, incomplete involvement of the temporal hemifields in both eyes was the most frequent event (22%), followed by anterior junction syndrome (13%). The latter entity at least clinically indicates the proximity of the pre-chiasmal ipsilateral optic nerve and decussating fibres emanating from the inferior nasal hemiretina of the fellow eye. However, this cannot provide conclusive evidence for the existence of anterior Wilbrand's knee.